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Biomedical subjects

Z Hrubec

Publications and source records attributed to Z Hrubec.

At least 37 records · Page 2Linked to original sources
PubMed1989

Trends in mortality from coronary heart disease and stroke among U.S. veterans; 1954-1979.

A cohort of nearly 300,000 insured veterans (Dorn Cohort), experienced a much greater percent decline in CHD death rate over the period, 1954-1979, than the population of the U.S., while for stroke, the percent decline in death rate was virtually the same as the U.S. For CHD, greater percent declines were noted over the study period for non-smokers compared to cigarette smokers, for professionals compared to non-professionals and for persons with high socioeconomic scores (SES) compared to those with low scores. In each group, younger persons experienced greater percent declines than older persons. For stroke, non-smokers experienced a somewhat greater percent decline in rate than smokers but this did not hold true for all age groups. Unlike CHD, professionals experienced a smaller percent decline in their stroke death rate than non-professionals, as did persons with high SES compared to those with low SES. The contradictory patterns observed for the two diseases with respect to occupation and SES suggest that the risk factors for stroke and coronary heart disease are not exactly the same. Throughout, the findings were much more convincing for CHD than for stroke.

Aged↗
PubMed1989

Cancer risk following pernicious anaemia.

A computer-based file of all Veterans Administration (VA) hospitalisation records for the period 1969-1985 was used to identify and follow for cancer development a cohort of 5,161 white males with pernicious anaemia. A total of 34,915 person-years were accrued, with an average length of follow-up of 6.8 years. A total of 481 cancers were diagnosed, slightly higher than the number expected (SIR = 1.2). Significant excesses were observed for cancers of the buccal cavity and pharynx (1.8) and stomach (3.2), and for melanoma (2.1), multiple myeloma (2.1), myeloid leukaemia (3.7) and other and unspecified leukaemia (4.0). Although the excess for stomach cancer was highest in the first year after diagnosis in a VA hospital, risks of 2-fold or greater persisted throughout the study period. The majority of leukaemias occurred in the first year of follow-up, but some excess risk continued beyond this time. The elevated risk of buccal and pharyngeal cancers may relate to heavy alcohol intake among this population, although risks remained high even when the cohort was restricted to patients without an admission for alcoholism. Although an elevated risk of stomach cancer among pernicious anaemia patients is consistent with most previous surveys, the low absolute risk suggests that the cost-effectiveness of intensive screening should be reassessed.

Adolescent↗
PubMed1989

Mortality and career radiation doses for workers at a commercial nuclear power plant: feasibility study.

Career radiation doses for 8,961 male workers at the Calvert Cliffs Nuclear Power Plant (CCNPP) were determined for both utility (n = 4,960) and contractor (n = 4,001) employees. Workers were followed from the time of first employment at CCNPP (including plant construction) to the end of 1984 (mean follow-up = 5.4 y). Plant operation began in 1975. The mean duration of employment was 1.9 y at CCNPP and 3.1 y in the nuclear industry. Career radiation doses were determined from dosimetry records kept by the utility company and the U.S. Nuclear Regulatory Commission (NRC). For all exposed workers, the average career dose was 21 mSv and was higher for contractor (30 mSv) than utility (13 mSv) workers. Career doses were also higher among those employed in the nuclear industry for greater than or equal to 15 y (111 mSv) and among workers classified as health physicists (56 mSv). Cumulative doses of greater than or equal to 50 mSv were received by 12% of the workers; the maximum career dose reported was 470 mSv. The availability of social security numbers for practically all employees facilitated record-linkage methods to determine mortality; 161 deaths were identified. On average the workers experienced mortality from all causes that was 15% less than that of the general population of the U.S., probably due to healthier members of the population being selected for employment. Our investigation demonstrates that historical information is available from which career doses could be constructed and that, in principle, it is feasible to conduct epidemiologic studies of nuclear power plant workers in the U.S. Although difficult, the approach taken could prove useful until such time as a comprehensive registry of U.S. radiation workers is established.

Adult↗
PubMed1989

Trends in mortality from chronic obstructive pulmonary disease among U.S. veterans: 1954 to 1979.

Recent trends in chronic obstructive pulmonary disease (COPD) mortality are described for a cohort of nearly 300,000 insured veterans who were followed for survival from 1954 through 1979. Death rates from COPD for the veterans by smoking status were compared with U.S. death rates for white males 55 to 84 yr of age over the same period. The main findings were that the veterans experienced sharp increases in COPD mortality over the 26-yr study period, much like the U.S. findings. However, the observed increases were not as great as those for the United States. The COPD rates for veterans who were cigarette smokers showed the same pattern as for all veterans. Some important differences by age were noted. Thus, for ages 60 to 64 and 65 to 69, the direction of the trend among veterans appeared to change from initial increases in the COPD death rate to later decreases while at the same time the three oldest age groups (70-74, 75-79, and 80-84) continued to experience increases in mortality over the whole period. These findings were similar to those for the United States. Several possible explanatory factors for these changes are discussed.

Age Factors↗
PubMed1988

A comparative study on different methods of measuring Rn concentrations in homes.

Three methods of measuring 222Rn concentration in homes were compared. In 91 dwellings, measurements were made with thermoluminescence dosimeters (TLDs) for two weeks during the winter, with alpha track Track Etch type SF dosimeters (ATDs) for six months during the heating season and for one year. There was a high correlation between the TLD and the six-month ATD values (r = .83) and between the six-month and the one-year ATD values (r = .80). On the average, however, the arithmetic and geometric means of the ATD (six-month) values were approximately 50 Bq m-3 higher than the TLD values (p less than .0001). The six-month ATD values also were, on the average, approximately eight percent higher than the one-year values. This difference is probably caused by decreased ventilation during the colder part of the year. The results indicate that the measurement methods under study may be of value for exposure assessments in epidemiologic studies, but also that estimates of risk per unit radiation exposure should be interpreted with caution.

Housing↗
PubMed1987

The monozygotic twinning rate: is it really constant?

Weinberg's difference method, applied to twin birth statistics, usually shows a dependence of the MZ rate on maternal age, like a thin shadow of the DZ rate. Some of this MZ variation could be explained away by James' finding of more same-sex (SS) than opposite-sex (OS) DZ twins, the excess being mistakenly classified as MZ by Weinberg's assumption of equal numbers. By several methods one can extract a constant value for the MZ rate and a constant or nearly constant value for the DZ SS/OS ratio, but these "constants" are actually arbitrary and they vary between populations.

Birth Order↗
PubMed1987

Passive smoking and lung cancer in Swedish women.

The relation between passive smoking and lung cancer was examined by means of a case-control study in a cohort of 27,409 nonsmoking Swedish women identified from questionnaires mailed in 1961 and 1963. A total of 77 cases of primary carcinoma of the bronchus or lung were found in a follow-up of the cohort through 1980. A new questionnaire in 1984 provided information on smoking by study subjects and their spouses as well as on potential confounding factors. The study revealed a relative risk of 3.3, constituting a statistically significant increase (p less than 0.05) for squamous cell and small cell carcinomas in women married to smokers and a positive dose-response relation. No consistent effect could be seen for other histologic types, indicating that passive smoking is related primarily to those forms of lung cancer which show the highest relative risks in smokers.

Adult↗
PubMed1986

A twin study of human obesity.

Height, weight, and body mass index (BMI) were assessed in a sample of 1974 monozygotic and 2097 dizygotic male twin pairs. Concordance rates for different degrees of overweight were twice as high for monozygotic twins as for dizygotic twins. Classic twin methods estimated a high heritability for height, weight, and BMI, both at age 20 years (.80, .78, and .77, respectively) and at a 25-year follow-up (.80, .81, and .84, respectively). Height, weight, and BMI were highly correlated across time, and a path analysis suggested that the major part of that covariation was genetic. These results are similar to those of other twin studies of these measures and suggest that human fatness is under substantial genetic control.

Adult↗
PubMed1985

Zygosity partitioning of small twin samples.

When the Weinberg estimate of the proportion of monozygotic pairs is quite deviant from that in the source population, it is likely to be wrong because Weinberg's difference is much less stable than the zygosity proportions. A formula is proposed for the probability distribution of possible compositions of a small sample of twins based on sex concordance in the sample and zygosity proportions in the source population.

Female↗
PubMed1984

Familial factors in mortality with control of epidemiological covariables. Swedish twins born 1886-1925.

A Cox proportional hazard regression analysis was carried out that evaluated age-specific death risk among 21,890 twins born in Sweden during 1886 through 1925 and followed during 1962 through 1980. Cotwin's survival was used as the primary covariable, and auxiliary covariables were smoking, marital status and, among men, police registration for alcohol abuse. In each age, sex and zygosity group, except the oldest DZ males, cotwin's mortality had a significant, independent, positive relationship to the mortality risk of the individual. The auxiliary covariables, except marital status among females, had significant, independent, positive relationships to mortality among the youngest twins of both zygosity groups and in the middle age group of MZ twins. In the oldest age group, the death of MZ cotwins was the only variable significantly related to the individual's mortality. Heritability estimates for the age-specific probability or death risk, developed by different methods for different analysis groups, range between 0.4 and 0.6. They have reasonable internal consistency, are not much affected by the covariates, and are in agreement with other studies that did not control covariates.

Aged↗
PubMed1982

Contribution of familial factors to the occurrence of cancer before old age in twin veterans.

In an earlier report, we evaluated familial factors in deaths from all causes before age 62 among the 31,848 white male twin veterans who were followed during 1946-1978 through the National Academy of Sciences-National Research Council Twin Registry. We now report data for this group on twin concordances and heritabilities of cancer recorded on the death certificate as an underlying or associated cause. The study subjects have a mortality from cancer 0.88 times, and one from all causes 0.84 times, that of U.S. white males [12], but this is very similar to the mortality of other U.S. veterans [9]. Among 11,350 monozygotic (MZ) and 14,450 dizygotic (DZ) individuals in twin pairs alive on January 1, 1946, 1,162 MZ and 1,646 DZ individuals died before January 1, 1979. Cancer was diagnosed for 223 MZ and 323 DZ twins as an underlying or associated cause of death. Among the latter were 176 MZ and 274 DZ pairs with the only death in the pair a cancer death, 10 MZ and eight DZ pairs concordant for cancer, and 12 MZ and 14 DZ pairs in which the first death in the pair from cancer was followed by death of the other twin from another cause. When account is taken of the three MZ and two DZ pairs concordant for lung cancer, most likely related to cigarette smoking, the twin cancer death concordance rates are very low, and they are not appreciably different between the two zygosity groups. Genetic factors may be important in some specific forms of cancer. However, these data suggest that genetic factors and early familial environment, generally shared by twin-pair members, do not contribute much to mortality from most cancers between 30 and 60 years of age.

Adult↗
PubMed1981

Familial factors in early deaths: twins followed 30 years to ages 51-61 in 1978.

Subjects in the National Academy of Sciences-National Research Council Twin Registry of 31,848 male twin veterans were followed for mortality from 1 January 1946, or from the date of entry into military service if that was later, to 31 December 1978. During this time 3,573 deaths occurred among them, 837 due to trauma and 2,712 due to disease. Mortality from all causes for the entire follow-up period was 10.2% among 11,350 monozygotic (MZ) twins and 11.4% among 14,450 dizygotic (DZ) twins. Mortality of veterans is known to be favorable compared to U.S. males. Among U.S. males of the same ages as the two respective twin zygosity groups, a mortality of 13.9% would have been expected during this time period. Observed mortality from trauma was 2.3% for MZ twins and 2.5% for DZ twins, with 3.0% expected in either group. Observed mortality from all disease was 7.9% for MZ twins and 8.8% for DZ twins, with 10.9% expected in either group. For total mortality, the case twin concordance rates, based on individual deaths, were 28.2% among MZ twins and 17.7% among DZ twins. For trauma, respectively by zygosity, these concordance rates were 6.9% and 3.9%. In this sample, familial factors appear to be of little consequence in trauma deaths. For all disease the concordance rates were 30.1% and 17.4%. Estimating heritability of liability to death from disease, as proposed by Edwards (1969), provides values of h2 = r = 0.51 for MZ twins, h2 = 2r = 0.48 for DZ twins, and h2 = 2(rMZ-rDZ) = 0.54 using data for the two zygosity groups combined.

Adult↗
PubMed1981

Evidence of genetic predisposition to alcoholic cirrhosis and psychosis: twin concordances for alcoholism and its biological end points by zygosity among male veterans.

Medical histories of the 15,924 male twin pairs in the National Academy of Sciences-National Research Council Twin Registry were examined to determine, within pairs, concordances for alcoholism and its medical end points. Prevalences per 1,000 among individual twin subjects were 29.6 for alcoholism, 4.1 for alcoholic psychosis, 14.2 for liver cirrhosis, and 2.1 for pancreatitis. Prevalences were similar to monozygotic (MZ) and dizygotic (DZ) twins. Prevalences in percent among co-twins of diagnosed subjects, that is case-wise twin concordance rates, were, respectively, by diagnosis: alcoholism: 26.3 (MZ), 11.9 (DZ); alcoholic psychosis: 21.1 (MZ), 6.0 (DZ); and liver cirrhosis: 14.6 (MZ), 5.4 (DZ). No twin pairs concordant for pancreatitis were found. The greater concordance for alcoholic psychosis and for liver cirrhosis among MZ than DZ twins could not be explained by the difference in alcoholism concordance between them. The difference in concordance between MZ and DZ twins persisted when, in addition, it was assumed that only half of the actually occurring cases of alcoholism and of each of the end points have been ascertained. These results provide evidence in favor of genetic predisposition to organ-specific complications of alcoholism and should serve to stimulate searches for the underlying biochemical mechanisms.

Alcoholism↗